Tooth polishing cup



April 23, 1957 A. o. WISEMAN TOOTH POLISHING CUP Filed June 27, 1955 INVEN TOR. ADOLPH D. W/S'MA/V ATTORNEYS TOOTH POLISHING CUP Adolph D.Wiseman, San Francisco, Calif. Application June 27, 1955, Serial No.518,189 6 Claims. (Cl. 32-59) V This invention relates to a toothpolishing cup of generally the type shown in my United States LettersPatent No. 2,017,881 of October 22, 1935.

One of the objects of the present invention is the provision of a toothpolishing cup having means for definitely limiting the width of theradially outwardly extending lip that is formed along the free edges ofthe cup when pressure is applied to the cup in a polishing operation,and at the same time such means provides a reservoir for a supply oftooth polishing material within the cup for delivery to such lip.

In explanation of the above, polishing cups are usually of relativelysoft rubber or the like, and when the free edges along the open side ofthe cup are pressed against a tooth in a polishing operation, themarginal portion of the cup, around said free edges will stretch so asto form a radially outwardly projecting lip. Heretofore, the Width ofthis lip has been entirely dependent upon the pressure applied by thedentist, and since this lip will extend under the free, unattachedmargin of the gum tissue for cleaning each tooth along the gum line,injury to the connecting periodental fibers which attach the gum tissuesto the neck of the tooth has resulted from the application of pressuregreater than is sufiicient to clean the teeth to such fibers.

While the provision of reinforcing ribs within a cup, extending axiallythereof, are of value in stifiening the portion of the cup that carriessuch ribs, they do not positively restrict the width of the lip that isadapted to project radially outwardly of the cup along the free edge ofthe latter, and furthermore, a pressure on the cup sulficient to spreadthe outer lip against the teeth to the ends of axially extending ribswithin the cup results in a vibration against the teeth when the cup isrotated due to the ends of such ribs.

The polishing cup as disclosed in the said patent is illustrative ofthis type of structure.

Where a polishing cup encloses bristles, it is obvious that there is nostorage space for an abrasive, and the bristles would prevent thedesired spreading of the lip.

With the present invention, the outer marginal portion of the cup canotbe expanded beyond a certain degree, and when so expanded the polishingarea is substantially extended without decreasing the capacity of thereservoir that holds the abrasive to be fed to the polishing lip, and itis one of the objects of the present invention to provide a structurethat enables the accomplishment of the above results.

Other objects and advantages will appear in the description and in thedrawings.

In the drawings,

Fig. 1 is a greatly enlarged vertical sectional view taken through a cuplengthwise of the latter with said cup illustrated as being mounted on ashank piece that, in turn, is adapted to be held in a chuck or handpiece.

Fig. 2 is a top plan view of the cup of Fig. 1.

Fig. 3 is a greatly enlarged view, partly in section and 2,789,352Patented Apr. 23, 1957 .that the cup is relatively small and thethickness of its side walls relatively thin as compared with thedrawings.

In detail, the cup is generally designated 1, and is preferably-formedof soft rubber or the like and may be provided with a base 2 that isformed with a socket 3 for removably securing the cup onto a shank piecegenerally designated 4, which shank piece has a bulbous end 5 adapted tobe held in socket 3. The shank piece includes a shank 6 for securementin a dental handpiece.

The present invention is not particularly concerned with the manner inwhich the cup is held onto a handle or to a shank piece or dentalhandpiece, hence the above description is merely intended to beillustrative of one way in which the cup may be supported.

. The base 2 provides a bottom wall 7 for the cup, and

the; lateral sides 8 of the cup preferably extend slightly divergentlyoutwardly from said base, terminating in an outer marginal portion orlip 9 that is coextensive with said side walls. The marginal portion orlip 9 has the circular outer free edge 10 of the cup 1.

Since the taper of walls 8 is quite slight, as indicated in thedrawings, said walls may be said to be generally cylindrical, althoughsaid walls actually form the frustum of a cone sovthat the cup portionis frusto-conical in shape with the closed bottom at the smaller end andthe open end at the larger diameter end, and the said walls becomeprogressively thinner in direction outwardly of the base 2.

At the juncture between the lip portion 9 and the remainder of the cup,and which juncture is adjacent to but is spaced from the free end edge10, is an internal radially inwardly projecting rib 12, the upper andlower sides (radially facing sides) of which extend convergently indirection radially inwardly to intersect along a line defining the innerdiameter of said rib.

While the walls of the lip 9 may be substantially of uniform thicknessaxially of the cup, this thickness is less than the minimum thickness ofwalls 8 which is immediately below rib 12, and the upper slanted surface13 of the rib is substantially wider in direction transversely of therib than the lower side 14 of the rib. This is important for the reasonthat when the lip 9 is flattened against a tooth, such as indicated at15 in Fig. 3, not only i the inner surface of the lip 9 against thetooth, but also an additional width equal to the thickness of the wall 8at the rib, and part, if not all, of the upper surface 13 of the rib.Thus, while the rib 12 will restrict the distance that the lip 9 willextend radially outwardly of the cup, it will also provide an additionalpolishing surface that is continuous around the cup.

The gum tissue 17 is free from the tooth along the gum line, and as thelip 9 cannot expand beyond the limit permitted by the rib 12, it will beseen that with the present design, the lip is of a width that cannotextend so far. below the gum as to injure the periodental fibers whichattach the gum tissue to the neck of the tooth, as would be likely tooccur, and frequently does occur where an accidental additional pressureon the cup would expand the lip so that its outer edge wouldobjectionably engage said fibers in a tooth polishing operation.

The inner sides of the lip 9 may be formed with uniform ridges 21. Inthemselves, such ridges are not new and heretofore have been providedfor the purpose of providing greater efliciency in a polishingoperation, since araaaaa the abrasive powder or material passesbetweensuchridged portion and the surfaces of the teeth. In the presentinstance, the lower ends of said ribs, as seen in Fig. 1 integrallyconnect with the rib 12,- lience tend to pull the surface 13 of the ribagainst the surface of the teeth when tension is placed on these ribs byflexing the lip 9 outwardly. Also said ribs will reinforce the' lipalong the line of juncture between the lip 9 and the rib The portion ofthe cup 1 below rib 12 provides a reservoir 18 for the tooth polishingmaterial 19 (Fig. 3) which may be powd'er, paste or a slurry, and theprovision of lip 12 prevents this polishing material from beingdischarged too rapidly onto the surfaces of the teeth. Inasmuch as theinner surface '20 of the walls 7 taper outwardly in direction toward therib 12, are material in the reservoir 18 will move to the rib, where itsmovemen: wil be checked by the rib, but 'said material will be pushedradially inwardly ever the lower surface 14 or the rib, and thengradually onto the outer surface 13 or the rib and finally onto theridged inner surface of the lip 9. In this operation, it is understoodthat the cup is being rotated about its axis, hence centrifugal forcewill be'acting on the abrasive material.

It i to be understood that the specific description is not intended tobe restrictive of the invention, but merely illustrative or a preferredform. Also the term rubber is not to be considered necessarilyrestrictive to conventi'onal rubber but is intended to cover anymaterial having the necessary characteristics which are found to existin rubber.

l. A dental tool comprising: a soft rubber tooth polishing cup forholding abrasive material-and having 'a bottom wall and generallycylindrical side walls and an annular free outer edge, an annular,radially inwardly directed rib coaxial with said side walls projectinginto said clip, said "rib being space-d between said free edge and saidbottom wall and closer to the former, the portion of said's'ide Wall'sbetween said rib and said free "edgedefining a'readily distortableflexible annular-lip adapted to stretch to a radially outwardlyextending positionupon application of pressure on said clip axiallythereof in the directio'n of said free edge when the latter 'is againsta tooth.

2. A dental tool comprising a "soft rubbertoothpolishing cup for holdingabrasive material having a "bottom wall 'and-"ge' n'erally' cylindricalside walls extending away from"said bottom wall and tcrmina ting in a nannular lip remote "from said bottom wall, an annular rib integral withs'a'id'-'cup, the walls ofsaid lip being inclined outwfa'r'clly'axi'ally of said cup 'audbeing relatively thin and readily "stretchable"to a position e) ;tcn ding'radia1 ly autwar dlyof the axis'of said'cupuponapplication espressure'on -said cup axially thereof in a directiontoward said lip when "the latter is against a tooth 'wher'eby"'theradially inwardly facing surface of "said lip 'WiIPengag'e saidtooth'for 'polishingthelatter, and an annular radiallyinwardlyprojecting rib integral with said-cup at thejunc turebetweensaid lip and the remainder of said cup having an axiallyoutwardly facing surface that is coextensive with said inner 'surfaceof'said lip when "said-lipis in polishing position extending radiallyoutwardly of said axis.

3 A dental tool comprising: a soft rubber tooth polishing'cupfor'holding abrasive material and h'aving'a bottom wall andgenerally cylindrical side walls and anannular free outer edge,anfannulanradially inwardly'directed rib coaxialjwith'said side wallsprojecting into sa'id'cup, said rib"being' spaced between said freeedge'and said bottom wall and closer to the former, the. portion 6r saidside walls betweensaid rib and said free edge defining ,a

readily distortable flexible annular lip adapted tostretch to a radiallyoutwardly extending position upon application of pressure on said cupaxially thereof in the direc tion of said free edge when the latter isagainst a tooth, said walls being slightly inclined outwardly relativeto the axis of said cup in a direct-ion away from said bottom wall.

4. A dental tool comprising a soft rubber cup having a bottom wall, sidewalls and an open end opposite to said bottom Wall, an annular radiallyinwardly projecting rib around said side walls integral therewith andcoaxial with said cup and spaced from said bottom wall for de fining abarrier to the free flow of abrasive material in said cup to said openend upon revolving said cup about its axis, said lip being relativelythin and adapted to stretch to a position projecting radially outwardlyrelative to said axis when said lip is in engagement with the surfaee ofa tooth and pressure is applied to said cup axially thereof toward saidtooth, the axially fa'cin g side of said rib generally facing saidbottom wall-beingslanted in cross sectional contour in a direction fromsaid side wall toward said lip rib and said side Wall being slantedoutwardly in direction away from said bottom wall whereby said abrasivematerial betweensaid rib and-*said -bottom Wall will be gradually 'movedacrosssa'id lip and to said lip upon said revolution-of said cup.

5. A dental tool comprising a'so'ft rnber frusto-conical polishing cupterminating at its larger diameter end in a free circular edge definingthe-outline of'the -open end of said cup and a base at the end of saidcup'opposite to said ope'nend providing a bottom wall for saidcup, anannular radially inwardly directed rib coaxialwithsaid cup and integraltherewith projecting into-the same at-"a point adjacent to but spacedfrom "saidfreeedge, ridges integrally connected at one of their'endswithsaid rib and integral with the marginal portion of said :cup alongsaid free edge and extending outwardly from said rib "relative to saidbottom Wall, said margi'nal-portionarid ridges being adapted to stretchto radially outwardly extending position "relative-to said rib uponapplication of pressure against said cup axially-thereof in directiontoward said free edges when the latter are in engagement with a tooth.

6. -A dental tool comprising an elongatedso'ftrubber"polishing'cuphaving a bottom at one end and *afree circular-edge at-the-opposite end defining the openend ofisaidcup, frusto-conicalsidewalls extending between said free "edge and 5 said bottom I wallcarrying said" free 'edge'with said free edge being atthelargeshdiameter end 'of said side walls an' annular rib integral"with-"said *side walls adjacent to but spaced from-said free=edge"'tlierewith'and integrally connected at one of their ends iwithzthesurface of said rib that faces generally toward-said free. edge, saidridges extending substantially between said rib and free edge' axiallyof said cup wherebytension in' anaxially outer'dircctionwill be placedon said surface of said rib when said lip and the ridges thereonarefiexed to=extend radially outwardly of the axis of said cup.

References Cited in the file of this patent UNITED-STATES PATENTSf'.1.1;'62'6, 1f21 W yn --;.-Apr. -,2 ,-:l227 "2,017,881 'Wiseman-lIOct, 22,1935

